The attachment of satellite-linked transmitters and time-depth recorders are important
techniques for obtaining information on the movements and diving behavior of small
cetaceans. Drag caused by these telemetry and data logger packages may influence the
longevity of attachment and possibly induce changes in the behavior of tagged animals. To
quantify the drag caused by these tags, a life-size fiberglass model of a harbor porpoise was
mounted in a wind tunnel and fitted with various tag designs. The proportional increase in
drag caused by three tag designs varied from 0.27 to 0.66. The tag design with the least
increase in drag exhibited the longest attachment on wild porpoises (212 days). Research is
required to investigate the energetic costs of this increase in drag to tagged dolphins and
porpoises.

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